Cement composition and manufacturing method for cement cured body using same

Patent metadata

Field	Value
Publication number	US-10577282-B2
Application number	US-201916423498-A
Country	US
Kind code	B2
Filing date	May 28, 2019
Priority date	Aug 25, 2014
Publication date	Mar 3, 2020
Grant date	Mar 3, 2020

Abstract

Provided is a cement composition that has high fluidity (for example, a 0-drop flow value of 200 mm or more) before curing and exhibits high compressive strength (for example, 320 N/mm2 or more) after curing. The cement composition includes a cement, a silica fume having a BET specific surface area of from 10 m2/g to 25 m2/g, an inorganic powder having a 50% cumulative particle size of from 0.8 μm to 5 μm, a fine aggregate having a maximum particle size of 1.2 mm or less, a water reducing agent, an antifoaming agent, and water. The ratio of the cement is from 55 vol % to 65 vol %, the ratio of the silica fume is from 5 vol % to 25 vol %, and the ratio of the inorganic powder is from 15 vol % to 35 vol % in the total amount of 100 vol % of the cement, the silica fume, and the inorganic powder.

First claim

The invention claimed is:

1. A method of producing a cementitious cured body made of a cement composition, the cement composition comprising:
cement;
silica fume having a BET specific surface area of from 10 m 2 /g to 25 m 2 /g;
an inorganic powder having a 50% cumulative particle size of from 0.8 μm to 5 μm;
a fine aggregate having a maximum particle size of 1.2 mm or less;
a water reducing agent;
an antifoaming agent; and
water,
wherein a ratio of the cement is from 55 vol % to 65 vol %, a ratio of the silica fume is from 5 vol % to 25 vol %, and a ratio of the inorganic powder is from 15 vol % to 35 vol % in a total amount of 100 vol % of the cement, the silica fume, and the inorganic powder,
the method comprising:
a molding step of setting the cement composition into a mold to provide an uncured molded body;
a room temperature curing step of subjecting the uncured molded body to sealed curing or atmospheric curing at from 10° C. to 40° C. for 24 hours or more, followed by demolding the molded body from the mold, to thereby provide a cured molded body;
a water absorbing step of immersing the cured molded body into boiling water at ambient pressure, and then cooling the water to 40° C. or less while keeping the cured molded body immersed in the water;
a heat curing step of subjecting the cured molded body after being immersed in the water to steam curing or hot water curing at from 70° C. to 95° C. for 24 hours or more, to thereby provide a cured body after heat curing; and
a high-temperature heating step of heating the cured body after the heat curing at from 150° C. to 200° C. for 24 hours or more, to thereby provide the cementitious cured body.

2. The method according to claim 1 , wherein the cement is a cement which is not subjected to polishing treatment, and the BET specific surface area of the silica fume is from 15 m 2 /g to 25 m 2 /g.

3. The method according to claim 1 , wherein
the cement comprises coarse particles each having a particle size of 20 μm or more in which an angular surface portion is deformed into a rounded shape and fine particles each having a particle size of less than 20 μm; and
the cement has a 50% weight cumulative particle size of from 10 μm to 18 μm and a Blaine specific surface area of from 2,100 cm 2 /g to 2,900 cm 2 /g.

4. The method according to claim 1 , wherein the cement composition comprises one or more kinds of fibers selected from the group consisting of metal fibers, organic fibers, and carbon fibers, in which a ratio of the fibers in the cement composition is 3 vol % or less.

5. The method according to claim 1 , wherein the cementitious cured body has a compressive strength after curing of 320 N/mm 2 or more.

6. The method according to claim 1 , wherein the room temperature curing step comprises demolding the cured molded body from the mold at a time when the cured molded body exhibits a compressive strength of from 20 N/mm 2 to 100 N/mm 2 .

7. The method according to claim 1 , wherein
the cement comprises coarse particles each having a particle size of 20 μm or more in which an angular surface portion is deformed into a rounded shape and fine particles each having a particle size of less than 20 μm,
the cement has a 50% weight cumulative particle size of from 10 μm to 18 μm and a Blaine specific surface area of from 2,100 cm 2 /g to 2,900 cm 2 /g, and
the method includes a polishing step of subjecting particles of moderate-heat Portland cement or low-heat Portland cement to a polishing treatment to obtain the coarse particles and the fine particles.

Assignees

• Taiheiyo Cement Corp

Inventors

• Nakayama Risa
• Kono Katsuya
• Tada Katsuhiko
• Mori Hiroaki
• Sugiyama Shingo
• Maehori Shinpei

Classifications

• C04B2201/52

  High compression strength concretes, i.e. with a compression strength higher than about 55 N/mm2, e.g. reactive powder concrete [RPC] · CPC title

• C04B40/02

  Selection of the hardening environment · CPC title

• C04B7/02

  Portland cement · CPC title

• C04B28/02

  containing hydraulic cements other than calcium sulfates · CPC title

• C04B2103/302

  Water reducers · CPC title